Solid state lighting devices with point contacts and associated methods of manufacturing

ABSTRACT

Solid state lighting (“SSL”) devices with improved contacts and associated methods of manufacturing are disclosed herein. In one embodiment, an SSL device includes a first semiconductor material, a second semiconductor material spaced apart from the first semiconductor material, and an active region between the first and second semiconductor materials. The SSL device also includes an insulative material on the first semiconductor material, the insulative material including a plurality of openings having a size of about 1 nm to about 20 μm, and a conductive material having discrete portions in the individual openings.

TECHNICAL FIELD

The present disclosure is related to solid state lighting (“SSL”)devices with point contacts and associated methods of manufacturing.

BACKGROUND

Mobile phones, personal digital assistants (“PDAs”), digital cameras,MP3 players, and other portable electronic devices utilize SSL devices(e.g., light emitting diodes (LEDs)) for background illumination. SSLdevices are also used for signage, indoor lighting, outdoor lighting,and other types of general illumination. FIGS. 1A and 1B arecross-sectional and plan views, respectively, of a conventional SSLdevice 10. As shown in FIGS. 1A and 1B, the SSL device 10 includes asubstrate 12 carrying an LED structure 11 having N-type gallium nitride(GaN) 14, GaN/indium gallium nitride (InGaN) multiple quantum wells(“MQWs”) 16, and P-type GaN 18. The SSL device 10 also includes a firstterminal 20 in contact with the N-type GaN 14 and a second terminal 22in contact with the P-type GaN 18. The first terminal 20 includes aplurality of contact fingers 21 (three are shown for illustrationpurposes) coupled to one another by a cross member 23. The secondterminal 22 includes a sheet-like structure.

In operation, a continuous or pulsed electrical voltage is appliedbetween the first and second terminals 20 and 22. In response, anelectrical current flows from the first terminal 20, through the N-typeGaN 14, the GaN/InGaN MQWs 16, and the P-type GaN 18, to the secondterminal 22. The GaN/InGaN MQWs 16 then convert a portion of theelectrical energy into light. The generated light is extracted from theN-type GaN 14 of the SSL devices 10 for illumination, signage, and/orother suitable purposes.

The SSL device 10, however, may have low light extraction efficiencies.According to conventional techniques, the first and second terminals 20and 22 typically include aluminum, copper, or other nontransparentconductive materials. As a result, light generated in areas directlybetween the first and second contacts 20 and 22 can be difficult toextract. On the other hand, the areas directly between the first andsecond contacts 20 and 22 produce the highest intensity of light in theSSL device 10. As a result, a large portion of the light generated inthe SSL device 10 may not be extracted, which results in low lightextraction efficiencies. Accordingly, several improvements in increasinglight extraction efficiency in SSL devices may be desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic cross-sectional diagram of an SSL device inaccordance with the prior art.

FIG. 1B is a schematic plan view of the SSL device in FIG. 1A.

FIGS. 2A-2C are schematic cross-sectional diagrams of a portion of anSSL device illustrating a current spread in the SSL device in accordancewith embodiments of the technology.

FIG. 3A is a plan view of an SSL device with point contacts inaccordance with embodiments of the technology.

FIGS. 3B and 3C are cross-sectional views of a portion of the SSL devicein FIG. 3A.

FIG. 3D is a bottom view of a portion of the SSL device in FIG. 3B.

FIG. 4A is a cross-sectional view of another SSL device with pointcontacts in accordance with embodiments of the technology.

FIG. 4B is a plan view of a portion of the SSL device in FIG. 4A.

FIG. 5A is a cross-sectional view of another SSL device with pointcontacts in accordance with embodiments of the technology.

FIG. 5B is a plan view of a portion of the SSL device in FIG. 5A.

DETAILED DESCRIPTION

Various embodiments of SSL devices with point contacts and associatedmethods of manufacturing are described below. As used hereinafter, theterm “SSL device” generally refers to devices with LEDs, organic lightemitting diodes (“OLEDs”), laser diodes (“LDs”), polymer light emittingdiodes (“PLEDs”), and/or other suitable sources of radiation other thanelectrical filaments, a plasma, or a gas. The term “light extractionefficiency” generally refers to a ratio of the light extracted from anSSL device to the total light generated in the SSL device. A personskilled in the relevant art will also understand that the technology mayhave additional embodiments, and that the technology may be practicedwithout several of the details of the embodiments described below withreference to FIGS. 2A-5B.

FIGS. 2A-2C are schematic cross-sectional diagrams of a portion of anSSL device 100 illustrating current spread profiles in the SSL device inaccordance with embodiments of the technology. As shown in FIGS. 2A-2C,the SSL device 100 can include a substrate material 102, a firstterminal 120, a first semiconductor material 104, an active region 106,a second semiconductor material 108, and a second terminal 122 inseries. In the illustrated embodiment, the first and second terminals120 and 122 are arranged vertically relative to each other. In otherembodiments, the first and second terminals 120 and 122 can also bearranged laterally relative to each other or can have other suitablecontact configurations, as discussed in more detail below with referenceto FIGS. 5A and 5B. In any of these embodiments, the SSL device 100 canoptionally include a reflective material (e.g., a silver film), acarrier material (e.g., a ceramic substrate), an optical component(e.g., a collimator), and/or other suitable components.

In certain embodiments, the substrate material 102 can include silicon(Si), at least a portion of which has the Si(1,1,1) crystal orientation.In other embodiments, the substrate material 102 can include siliconwith other crystal orientations (e.g., Si(1,0,0)), AlGaN, GaN, siliconcarbide (SiC), sapphire (Al₂O₃), zinc oxide (ZnO₂), a combination of theforegoing materials, and/or other suitable substrate materials.

The first and second semiconductor materials 104 and 108 can beconfigured as cladding components for the active region 106. In certainembodiments, the first semiconductor material 104 can include N-type GaN(e.g., doped with silicon (Si)), and the second semiconductor material108 can include P-type GaN (e.g., doped with magnesium (Mg)). In otherembodiments, the first semiconductor material 104 can include P-typeGaN, and the second semiconductor material 108 can include N-type GaN.In further embodiments, the first and second semiconductor materials 104and 108 can individually include at least one of gallium arsenide(GaAs), aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide(GaAsP), gallium(III) phosphide (GaP), zinc selenide (ZnSe), boronnitride (BN), AlGaN, and/or other suitable semiconductor materials.

The active region 106 can include a single quantum well (“SQW”), MQWs,and/or a bulk semiconductor material. The term “bulk semiconductormaterial” generally refers to a single grain semiconductor material(e.g., InGaN) with a thickness greater than about 10 nanometers and upto about 500 nanometers. In certain embodiments, the active region 106can include an InGaN SQW, GaN/InGaN MQWs, and/or an InGaN bulk material.In other embodiments, the active region 106 can include aluminum galliumindium phosphide (AlGaInP), aluminum gallium indium nitride (AlGaInN),and/or other suitable materials or configurations.

In certain embodiments, the first semiconductor material 104, the activeregion 106, and the second semiconductor material 108 can be formed onthe substrate material 102 via metal organic chemical vapor deposition(“MOCVD”), molecular beam epitaxy (“MBE”), liquid phase epitaxy (“LPE”),and/or hydride vapor phase epitaxy (“HVPE”). In other embodiments, atleast one of the foregoing components may be formed via other suitableepitaxial growth techniques.

The second terminal 122 can include a sheet-like structure constructedfrom copper (Cu), aluminum (Al), silver (Ag), gold (Au), platinum (Pt),and/or other suitable metals or metal alloys. Techniques for forming thesecond terminal 122 can include MOCVD, MBE, spray pyrolysis, pulsedlaser deposition, sputtering, electroplating, and/or other suitabledeposition techniques.

The first terminal 120 can have a generally similar structure as thefirst terminal 20 shown in FIG. 1B. For example, the first terminal 120can include a plurality of contact fingers 121 connected to one anotherby a cross member 123. The contact fingers 121 and/or the cross member123 can individually include an elongated structure and/or othersuitable structures. The contact fingers 121 and the cross member 123can be constructed from copper (Cu), aluminum (Al), silver (Ag), gold(Au), platinum (Pt), and/or other suitable metals or metal alloys. Inother embodiments, the contact fingers 121 and cross member 123 can bemade from a transparent conductive oxide. Though three contact fingers121 are shown for illustration purposes in FIGS. 2A-2C, in otherembodiments, the SSL device 100 can include one, two, four, or any othersuitable number of contact fingers.

It has been recognized that light extraction efficiency in the SSLdevice 100 can be inversely related to an area of the first terminal120. As shown in FIGS. 2A-2C, the SSL device 100 can have a currentspread (identified as R₁, R₂, and R₃ in FIGS. 2A-2C, respectively) inthe SSL device 100. As used hereinafter, the term “current spread”generally refers to an effective area in the SSL device 100 throughwhich a current with an effective density flows between individualportions of the first terminal 120 and the second terminal 122. In FIGS.2A-2C, all the contact fingers 121 have generally the same length forillustration purposes. As a result, the area of the first terminal 120is represented by respective widths W (identified as W₁, W₂, and W₃ inFIGS. 2A-2C, respectively) of the contact fingers 121 for discussionpurposes. One of ordinary skill in the art will appreciate that thefollowing discussion is also applicable to the cross member 123 and/orother components of the first terminal 120.

As shown in FIGS. 2A-2C, the contact fingers 121 have different widthsas follows:

W₁>W₂>W₃

In operation, when an electrical voltage is applied between the firstand second terminals 120 and 122, an electrical current flows betweenthe first and second terminals 120 and 122. It is believed that a firstportion of the current may flow generally vertically following theshortest paths between the first and second terminals 120 and 122. It isalso believed that a second portion of the current may flow generallytransversely in the first semiconductor material 104 before flowingvertically toward the second terminal 122. As a result, the currentdensity tends to decrease along a direction away from the edges of thefirst terminal 120. Thus, the current spread can be generally greaterthan an area of the first terminal 120.

As discussed above, light generated beneath the first terminal 120 canbe difficult to extract. As a result, it is desirable that a ratio ofthe current spread to the width of the contact FIG. 121 is large. Asshown in FIG. 2B, when the contact fingers 121 are narrow (e.g., to lessthan about 0.5 mm), the ratio of current spread R₂ to width of thecontact fingers W₂ tends to increase from that of the current spread R₁to width of the contact fingers W₁ in FIG. 2A. As a result, a ratio ofthe area of the contact fingers 121 to the current spread increases asthe area decreases as follows:

$\frac{R_{1}}{W_{1}} < \frac{R_{2}}{W_{2}} < \frac{R_{3}}{W_{3}}$

Thus, more light may be generated in regions from which light may beeasily extracted to improve light extraction efficiency. Accordingly, itis advantageous to have a large number of small contacts than a smallnumber of large contacts.

Having a large number of small contacts can also improve the currentdensity profile in the SSL device 100. As shown in FIG. 2C, when thecontact fingers 121″ are narrowed below a threshold value (e.g., 0.1mm), the adjacent current spreads R3 can overlap to form overlappedareas 133. The overlapped areas 133 associated with contact fingers 121″can thus have a higher current density than in conventional devices toyield a more uniform current density profile in the SSL device 100.

As discussed above, light generated in areas underneath the contactfingers 121 may be difficult to extract, and as the area of the contactfingers 121 decreases, more light may be generated from areas offsetfrom the contact fingers 121 where it can be readily extracted from theSSL device 100. As a result, it may be advantageous to select (e.g.,reduce) the area of the contact fingers 121 (e.g., the width W) based ona target light extraction efficiency. However, the contact fingers 121and the cross member 123 with small areas may have high electricalimpedance and thus degrade the electrical performance of the SSL device100. As a result, the areas of the first terminal 120 may not be reducedexcessively. Rather, selecting the areas of the first terminal 120 is abalance between the degree of current spread and the electricalperformance (e.g., impedance) of the first terminal 120.

Several embodiments of the current technology can allow a high currentspread to area ratio

$\frac{R}{A}$

while maintaining a sufficient contact area for the second terminal 122by forming a plurality of point contacts. FIG. 3A is a plan view of anSSL device 200 with point contacts in accordance with embodiments of thetechnology. FIGS. 3B and 3C are cross-sectional views of orthogonalportions of the SSL device 200 in FIG. 3A. FIG. 3D is a bottom view of aportion of the SSL device 200 in FIG. 3B.

As shown in FIGS. 3A and 3B, the SSL device 200 can include a pluralityof insulative pads 126 on the first semiconductor material 104. Thecontact fingers 121 and cross member 123 of the first terminal 120 coverat least a portion of the pads 126. The pads 126 may be constructed fromsilicon dioxide (SiO2), silicon nitride (SiN), and/or other dielectricmaterials via chemical vapor deposition (“CVD”), atomic layer deposition(“ALD”), spin coating, and/or other suitable deposition techniques.

In FIG. 3A, the pads 126 are illustrated as all having a generallysimilar size and a rectilinear shape. In other embodiments, the pads 126can also have circular, oval, trapezoidal, and/or other suitable shapes.In further embodiments, at least one of the pads 126 can have differentshape, size, or other characteristics than the other pads 126. Eventhough sixteen pads 126 are illustrated in FIG. 3A, in otherembodiments, the SSL device 200 may include any suitable number of pads.

As shown in FIG. 3B, the pads 126 can individually include a firstsurface 126 a in contact with a surface 104 a of the first semiconductormaterial 104 and a second surface 126 b opposite the first surface 126a. The first terminal 120 can individually include a first portion 120 aon the second surfaces 126 b of the pads 126 and a second portion 120 bbetween adjacent pads 126. The second portion 120 b includes a pluralityof sections in contact with a portion of the surface 104 a of the firstsemiconductor material 104. As a result, the second portion 120 b formsan electrical connection with the first semiconductor material 104 whilethe first portion 120 a forms an interconnect that electrically couplesall sections of the second portion 120 b. Though the first and secondportions 120 a and 120 b are shown as having the same material ofconstruction and are generally homogeneous, in other embodiments, thefirst and second portions 120 a and 120 b may include differentmaterials.

As shown in FIG. 3C, the individual pads 126 separate the first portion120 a of the individual contact fingers 121 from the first semiconductormaterial 104. As a result, the first portion 120 a of the individualcontact fingers 121 is insulated from the first semiconductor material104. In the illustrated embodiment, the individual contact fingers 121have a smaller width than the corresponding pads 126. In otherembodiments, the individual contact fingers 121 can have generally thesame width than the corresponding pads 126.

FIG. 3D shows a plan view of the SSL device 200 at an interface betweenthe pads 126 and the first semiconductor material 104. As shown in FIG.3D, the second portion 120 b of the first terminal 120 can have agenerally rectangular cross section and is arranged in an array.Sections of the second portion 120 b can individually form a pluralityof point contacts 127 as pillars, bumps, and/or other suitablestructures on the first semiconductor material 104. Adjacent pointcontacts 127 are separated from one another by one of the correspondingpads 126.

Several embodiments of the SSL device 200 can have high current spreadswhile maintaining an adequate total electrical contact area. In certainembodiments, the individual point contacts 127 can be sufficiently small(e.g., with a width less than about 0.1 mm) to induce large currentspreads in the SSL device 200. At the same time, the total area of thepoint contacts 127 may be maintained because the SSL device 200 mayinclude a sufficient number of point contacts 127 based on a targetcontact area.

Even though the pads 126 are discussed above with reference to FIGS.3A-3D as discrete structures, in other embodiments, the pads 126 can beinterconnected and generally conformal to the first semiconductormaterial 104. FIG. 4A is a cross-sectional view of an SSL device 200 inaccordance with additional embodiments of the technology. FIG. 4B is aplan view of a portion of the SSL device 200 in FIG. 4A. As shown inFIGS. 4A and 4B, the SSL device 200 includes an insulative material 125generally blanketing the first semiconductor material 104. Theinsulative material 125 can include a plurality of vias 128 individuallycontaining the second portion 120 b of the first terminal 120. Referringto FIG. 4B, the individual sections of the second portion 120 b in thevias 128 accordingly define an array of discrete point contacts 127. Theinsulative material 125 may be constructed from silicon dioxide (SiO2),silicon nitride (SiN), and/or other dielectric materials via chemicalvapor deposition (“CVD”), atomic layer deposition (“ALD”), spin coating,and/or other suitable deposition techniques.

FIG. 5A is a cross-sectional view of an SSL device 300 with pointcontacts in accordance with additional embodiments of the technology.FIG. 5B is a plan view of a portion of the SSL device 300 in FIG. 5A. Asshown in FIG. 5A, the SSL device 300 can include a plurality of openings140 extending from a surface 120 a of the first terminal 120 to thesecond semiconductor material 108. The SSL device 300 also includes anisolation material 130 on the surface 120 a of the first terminal 120and side walls 142 of the openings 140.

The second terminal 122 includes a first portion 122 a on the isolationmaterial 130 and a second portion 122 b in the openings 140. Parts ofthe second portion 122 b in the individual openings 140 form the pointcontacts 127. As a result, the second portion 122 b is in electricalconnection with the first semiconductor material 104 while the firstportion 122 a interconnects the second portion 122 b.

In certain embodiments, the individual point contacts 127 can have asize generally similar to a thickness of the first semiconductormaterial 104 or the second semiconductor material 108. For example, inone embodiment, the individual point contacts 127 can have a size (e.g.,a width, a length, a diameter, or a diagonal length) of about 2 μm toabout 4 μm. In other embodiments, the individual point contacts 127 canhave a size of about 1 nm to about 20 μm. In further embodiments, theindividual point contacts 127 can have other suitable sizes.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but that various modifications may be made without deviating from thedisclosure. In addition, many of the elements of one embodiment may becombined with other embodiments in addition to or in lieu of theelements of the other embodiments. Accordingly, the disclosure is notlimited except as by the appended claims.

I/We claim:
 1. A solid state lighting (SSL) device, comprising: a firstsemiconductor material; a second semiconductor material spaced apartfrom the first semiconductor material; an active region between thefirst and second semiconductor materials; and an electrical terminal onthe first semiconductor material, the electrical terminal including: aplurality of discrete point contacts spaced apart from one another, theindividual point contacts having a size of about 1 nm to about 20 μm;and an interconnect electrically connecting the plurality of discretepoint contacts.
 2. The SSL device of claim 1 wherein: the terminal is afirst terminal on the first semiconductor material; the SSL devicefurther includes a second terminal on the second semiconductor material;the second terminal is separated from the first terminal by the firstsemiconductor material, the active region, and the second semiconductormaterial; the first semiconductor material includes a P-type galliumnitride (GaN) material; the second semiconductor material includes anN-type GaN material; the active region includes at least one of a bulkindium gallium nitride (InGaN) material, an InGaN single quantum well(“SQW”), and GaN/InGaN multiple quantum wells (“MQWs”); the SSL devicefurther includes a plurality of insulative pads on the firstsemiconductor material; the point contacts individually include a bumpextending from the first semiconductor material; an adjacent pair of thebumps are separated from one another by one of the correspondinginsulative pads; and the interconnect includes an elongated structurethat electrically connects at least some of the plurality of pointcontacts.
 3. The SSL device of claim 1 wherein: the SSL device furtherincludes a plurality of insulative pads on the first semiconductormaterial; and an adjacent pair of the bumps are separated from oneanother by one of the corresponding insulative pads.
 4. The SSL deviceof claim 1 wherein: the SSL device further includes a plurality ofinsulative pads on the first semiconductor material; the point contactsindividually include a bump extending from the first semiconductormaterial toward the interconnect; and an adjacent pair of the bumps areseparated from one another by one of the corresponding insulative pads.5. The SSL device of claim 1 wherein: the SSL device further includes aplurality of insulative pads on the first semiconductor material; thepoint contacts individually include a bump extending from the firstsemiconductor material; an adjacent pair of the bumps are separated fromone another by one of the corresponding insulative pads; and theinterconnect includes an elongated structure that electrically connectsat least some of the plurality of bumps.
 6. The SSL device of claim 1wherein: the SSL device further includes an insulating material on thefirst semiconductor material; the insulating material includes aplurality of apertures; the apertures individually contain one of thepoint contacts extending from the first semiconductor material; and theinterconnect includes an elongated structure that electrically connectsat least some of the plurality of point contacts.
 7. The SSL device ofclaim 1 wherein: the SSL device further includes an insulating materialon the first semiconductor material; the insulating material includes aplurality of apertures; the point contacts individually include a bumpextending from the first semiconductor material; the aperturesindividually contain one of the bumps; and the interconnect includes anelongated structure that electrically connects at least some of theplurality of bumps.
 8. The SSL device of claim 1 wherein: the pointcontacts individually include a first conductive material; theinterconnect includes a second conductive material; and the first andsecond conductive materials are generally similar and homogeneous. 9.The SSL device of claim 1 wherein: the point contacts individuallyinclude a first conductive material; the interconnect includes a secondconductive material; and the first and second conductive materials aredifferent from each other.
 10. A solid state lighting (SSL) device,comprising: a first semiconductor material; a second semiconductormaterial spaced apart from the first semiconductor material; an activeregion between the first and second semiconductor materials; a firstterminal on the first semiconductor material; a plurality of aperturesextending from the first terminal into the second semiconductor materialvia the active region and the first semiconductor material, theapertures individually having a side wall; an isolation material havinga first isolation portion on the first terminal and a second isolationportion on the side walls of the apertures; and a second terminal in theplurality of apertures.
 11. The SSL device of claim 10 wherein theapertures have a size of about 1 nm to about 20 μm.
 12. The SSL deviceof claim 10 wherein: the second terminal is in contact with the secondsemiconductor material; and the second isolation portion electricallyisolates the second terminal from the active region, the firstsemiconductor material, and the first terminal.
 13. The SSL device ofclaim 10 wherein the second terminal includes a first contact portion onthe first isolation portion and a second contact portion in theaperture, the second contact portion being in contact with the secondsemiconductor material.
 14. The SSL device of claim 10 wherein: thesecond terminal includes a first contact portion on the first isolationportion and a second contact portion in the aperture, the second contactportion being in contact with the second semiconductor material; thefirst isolation portion isolates the first contact portion from thefirst terminal; and the second isolation portion isolates the secondcontact portion from the active region and the first semiconductormaterial.
 15. The SSL device of claim 10 wherein: the firstsemiconductor material includes a P-type gallium nitride (“GaN”); thesecond semiconductor material includes an N-type GaN; the active regionincludes at least one of a bulk indium gallium nitride (InGaN) material,an InGaN single quantum well (“SQW”), and GaN/InGaN multiple quantumwells (“MQWs”); the second terminal includes a first contact portion onthe first isolation portion and a second contact portion in theaperture, the second contact portion being in contact with the secondsemiconductor material; the first isolation portion isolates the firstcontact portion from the first terminal; and the second isolationportion isolates the second contact portion from the active region andthe first semiconductor material.
 16. A solid state lighting (SSL)device, comprising: a first semiconductor material; a secondsemiconductor material spaced apart from the first semiconductormaterial; an active region between the first and second semiconductormaterials; an insulative material on the first semiconductor material,the insulative material including a plurality of openings having a sizeof about 1 nm to about 20 μm; and a conductive material having discreteportions in the individual openings.
 17. The SSL device of claim 16wherein the insulative material includes a plurality of pads separatedfrom one another by one of the corresponding openings.
 18. The SSLdevice of claim 16 wherein the insulative material includes a sheet-likestructure blanketing the first semiconductor material, and wherein theopenings individually expose a portion of the first semiconductormaterial.
 19. The SSL device of claim 16 wherein: the conductivematerial is a first conductive material; the SSL device further includesa second conductive material on the second semiconductor material; theopenings individually expose a portion of the first semiconductormaterial; and the discrete portions of the first conductive material arein contact with the first semiconductor material.
 20. The SSL device ofclaim 16 wherein: the conductive material is a first conductivematerial; the SSL device further includes a second conductive materialbetween the insulative material and the first semiconductor material;the openings of the insulative material extend from the secondconductive material to the second semiconductor material through thefirst semiconductor material and the active region; and the discreteportions of the first conductive material are in contact with the secondsemiconductor material.
 21. A method of forming a solid state lighting(SSL) device, comprising: forming an SSL structure having a firstsemiconductor material, a second semiconductor material spaced apartfrom the first semiconductor material, and an active region between thefirst and second semiconductor materials; forming a plurality of pointcontacts on the first semiconductor material or the second semiconductormaterial, the point contacts individually having a contact area; andselecting a size of at least one of the point contacts based on a targetcurrent spread to contact area ratio.
 22. The method of claim 21 whereinselecting the size of at least one of the point contacts includesselecting a size of at least one of the point contacts such that twoadjacent current spreads overlap with each other.
 23. The method ofclaim 21 wherein selecting the size of at least one of the pointcontacts includes selecting a size of at least one of the point contactssuch that two adjacent current spreads overlap with each other whilemaintaining a total contact area above a target threshold.
 24. Themethod of claim 21, further comprising adjusting the target currentspread to contact area ratio based on a target light extractionefficiency of the SSL device.
 25. A device, comprising: a semiconductormaterial; an electrical terminal on the semiconductor material, theelectrical terminal including: a plurality of discrete point contactsspaced apart from one another, the individual point contacts having asize of about 1 nm to about 20 μm; and an interconnect electricallyconnecting the plurality of discrete point contacts.
 26. The device ofclaim 25 wherein: the electrical terminal is a first terminal; thesemiconductor material is a first semiconductor material; the firstterminal is on the first semiconductor material; the device furtherincludes a second semiconductor material and a second terminal on thesecond semiconductor material; the second terminal is separated from thefirst terminal by the first semiconductor material and the secondsemiconductor material; the first semiconductor material includes aP-type gallium nitride (GaN) material; the second semiconductor materialincludes an N-type GaN material; the device further includes a pluralityof insulative pads on the first semiconductor material; the pointcontacts individually include a bump extending from the firstsemiconductor material; an adjacent pair of the bumps are separated fromone another by one of the corresponding insulative pads; and theinterconnect includes an elongated structure that electrically connectsat least some of the plurality of point contacts.
 27. The device ofclaim 25 wherein: the electrical terminal is a first terminal; thesemiconductor material is a first semiconductor material; the firstterminal is on the first semiconductor material; the device furtherincludes a second semiconductor material and a second terminal on thesecond semiconductor material; the second terminal is separated from thefirst terminal by the first semiconductor material and the secondsemiconductor material; the device further includes a plurality ofinsulative pads on the first semiconductor material; the point contactsindividually include a bump extending from the first semiconductormaterial; and an adjacent pair of the bumps are separated from oneanother by one of the corresponding insulative pads.
 28. The device ofclaim 25 wherein: the device further includes a plurality of insulativepads on the semiconductor material; the point contacts individuallyinclude a bump extending from the first semiconductor material; and anadjacent pair of the bumps are separated from one another by one of thecorresponding insulative pads.